Stackable transport container

ABSTRACT

The invention relates to a stackable transport container which is adapted, when in a full condition filled with products, to be stacked with other transport containers on top of each other, or, when in an empty condition, to be placed together with other transport containers inside one another. In the left side wall and in the right side wall, respectively, grooves ( 602   a - f ) are formed which respectively have upper openings and lower groove stops. At the outside surface of the left side wall and at the outside surface of the right side wall, respectively, several guide pegs ( 600   a - f ) are formed. In a horizontal direction, the distances between the guide pegs are different from the distances between the upper openings ( 603   a - f ) of the grooves, thus preventing an upper transport container being inadvertently placed inside a lower transport container. Further, the distances between the guide pegs are chosen that placement of an upper container inside a lower container is possible in one direction only.

The present invention relates in general to a stackable transport container according to the preamble to claim 1, and in particular to a transport container which is adapted, when filled with products in a full condition, to be stacked with other transport containers on top of each other, or, when in an empty condition, to be placed together with other transport containers inside one another.

Transport containers have already been known for a long time for the transport of bread and similar foods from a large bakery to the individual shops, which are therefore also known as bread baskets.

These well known transport containers have a bottom and a front wall, a rear wall and two opposite side walls which extend upwards from the bottom at a right angle to form a receptacle open towards the top. The upper edges of the front wall, the rear wall and the side walls are formed with a kind of rail that is shaped so that it can engage with projections that are formed at the periphery of the underside of the container bottom of a transport container placed on top of it, if two of these transport containers are stacked on top of one another. In this way, two transport containers stacked on top of one another cannot be displaced relative to one another, as the projections on the underside of the container bottom of the upper transport container engage with the rail on the upper edge of the side walls of the lower transport container. These transport containers are generally used for the delivery of products. The filled containers being stacked on top of one another to form stacks, and then transported for example from a large bakery to the individual shops. The empty transport containers are then later transported back to the large bakery.

The disadvantage of these known transport containers is that, in their empty condition they cannot be placed one inside another to save space, which means that the transport volume of the filled transport containers (filled volume) is the same as the transport volume of the empty transport containers (empty volume).

To overcome this disadvantage, transport containers have been developed that can be both stacked on top of one another and placed inside one another. Transport containers of this type, when in a full condition filled with products, can be stacked on top of one another, generally with the lower surface of the bottom of an upper transport container resting on the upper edge of the side walls of a lower transport container. This creates a relatively large transport volume (filled volume) for each of the transport containers, which approximately corresponds to the product of the bottom surface and the height of the side walls of such a transport container. Should these transport containers be transported in an empty condition, it is naturally desirable that the transport volume of the empty transport containers (empty volume) should be kept as low as possible. For this reason the side walls of these known transport containers are inclined slightly outwards in order to enable the empty transport containers to be placed inside one another to save space. In this way a filled volume:empty volume ratio of approximately 2:1 can be achieved.

It is clear that these known transport containers must be constructed so as to be able to be stacked on top of one another and placed inside each other. Various suggestions for this have already been made in the state of the art. Documents EP 0 250 674 and EP 0 553 932 are mentioned as examples.

Another transport container is disclosed in DE 100 26 149. In a shown embodiment, this stackable transport container has a bottom, a front wall, a rear wall, a left side wall and a right side wall to form a receptacle open towards the top. Further, in each of the left side wall and the right side wall, four grooves are formed which have upper openings and lower groove stops. Four guide pegs are formed on each of the outside of the left side wall and the outside of the right side wall, wherein in horizontal direction the distances between the guide pegs are designed to be in mirror symmetry to each other and are different from the distances between the upper openings of the grooves.

As the distances between the guide pegs in horizontal direction are designed to be in mirror symmetry to each other and are different from the distances between the upper openings of the grooves, it is ensured that with horizontal alignment of two transport containers situated on top of one another, not all of the four guide pegs of the upper transport container can simultaneously penetrate into all of the four upper openings of the grooves of the lower transport container, thus preventing the upper transport container being unintentionally placed in the lower transport container. Consequently, the upper transport container can only be placed inside the lower transport container (condition of being one inside the other) by a type of plunging movement. Because of the configuration and arrangement of the four grooves and the four guide pegs, it is further possible that the transport containers can be stacked onto each other or inserted into each other in opposite orientations relative to each other.

This transport container known from DE 100 26 149 has several disadvantages. Because of the configuration with four grooves and the four guide pegs, wherein the distances of the guide pegs are arranged in mirror symmetry to each other, insertion into each other in opposite orientations (i.e. plunging movement from the front and from the rear) is possible. However, in some cases, it is not desired to allow insertion into each other from opposite directions as the transport containers have to be taken out or unstacked what is difficult, in particular, when a plurality of stacks of empty transport containers, which are inserted into each other, are located in a store house or in the storage place of a truck. When stacks of empty transport containers are arranged close to each other, it is an advantage when the transport containers can be displaced from the stack only in one direction (i.e. from the front side). However, when one of the transport containers is inserted in the stack with a wrong orientation, this transport container can not easily be displaced from the stack in rearward direction as another stack behind or a wall behind makes the displacement impossible. Therefore, the whole stack has to be pulled forward to allow rearward displacement of a transport container. Further, it has been found that a stacking apparatus for automatically unstacking in different directions is much more complicate and thus more expensive than an unstacking apparatus that is adapted for unstacking in only one direction. Of course, it is theoretically possible to provide colored markings at the transport containers to give a clear indication to the packing personnel in which orientation the known transport containers have to be inserted into each other; however, it has been found that these measures are prone to errors.

Another disadvantage of the transport container known from DE 100 26 149 is that the guide pegs, because of the possibility of insertion or disposal in opposite directions, can not be provided with reinforcements as these reinforcements would inhibit the insertion in at least one direction.

When, for example, a reinforcement in the form of a rip extending from the guide peg is provided, such a reinforcement has to be adapted for matching with the shape of the corresponding channel-shaped groove of the transport container underneath. However, when the upper transport container is inserted in the opposite (wrong) direction, the reinforcement rips at the guide pegs jam with the corresponding grooves.

Because of the missing reinforcements, the transport container has to be made from fiber-reinforced plastic material to ensure a sufficient strength especially of the guide pegs.

Therefore, it is the task of the present invention to provide containers which can be stacked at several levels, or placed inside each other, with the help of which the above-mentioned disadvantages of the transport containers according to the state of the art are overcome.

In particular, it is a task of the present invention, to provide a transport container which is designed to enable and guarantee safe stacking, so that transport containers stacked on top of one another cannot inadvertently be placed inside one another.

It is an additional main object to provide a transport container which can be inserted or unstacked in only one direction.

Further, the guide pegs can be reinforced by means of suitable measures such that a less stable but less expensive material can be used for the production of the transport container.

The transport containers according to the invention should also be compatible with the baker's trays mentioned at the start.

Finally the transport containers according to the invention should have no moving parts and be easy to clean.

These tasks are solved by a transport container with the features of claim 1. In the dependent claims, advantageous and preferred improvements of the transport container according to the invention are given.

The above transport containers for the transport of bread and similar foods were described to explain the state of the art. However, it is clear that the transport container according to the invention can also be used in other areas and is under no restrictions with regard to its size, use and the material used. Thus, the transport container according to the invention can be used for the transport of bread, vegetables, meat and eggs. Further, the transport container according to the invention can be used for example for the transport of machine parts, or for the transport of building rubble, in the form of a large steel container.

The transport container according to the invention has a bottom, a front wall, a rear wall, a left side wall and a right side wall, which can slope slightly outwards to form a receptacle open towards the top. The front wall and the rear wall may be of less height compared to both side walls; however, they can also be of the same height.

The left side wall and the right side wall (and, if desired, also the front wall and/or the rear wall) can be formed in a step-like configuration, wherein these walls each having a first substantially vertically extending, lower wall portion and a second substantially vertically extending upper wall portion, wherein the lower and upper wall portions being connected by means of a slightly inclined outwardly extending connecting portion. Thus, the upper wall portions define a horizontal substantially rectangular cross section plane which is larger than a horizontal substantially rectangular cross section plane defined by the lower wall portions. Further, the lower wall portions and the upper wall portions are sized so that the lower part of the transport container defined by the lower wall portions can be inserted in the upper part of an underneath transport container defined by the upper wall portions, i.e., the outer dimensions of the lower part substantially correspond to (or being less than) the inner dimensions of the upper part. Substantially at the level of the connecting portion, a horizontally extending flange is formed at the outer surface of the side walls and, if desired, at the front wall and/of the rear wall. When two containers are placed inside one another, the downward surface of the horizontal flange lies on the upward surface of the upper wall portions of the side walls and, if present, of the front wall and/of the rear wall. By means of such a construction, the strength of the transport container is increased. Further, the transport containers can be easier placed inside one another, and canting in this inserted condition is minimized.

In the left side wall and in the right side wall, at least two grooves are formed, which have upper openings at the upper edge of the side walls, and lower closed groove stops. These grooves are open towards the inner space of the container and, therefore, are accessible. Consequently, the grooves extend from the upper edge of the side walls, where the grooves are open and also accessible, down to the groove stops, which are preferably located at half way of the side walls and preferably in the lower half of the side walls. These grooves can be formed as channels in the inside surface or at the inner side of the side walls in question, or may extend completely through the side walls in the form of slits, making possible lower comicality of the side walls. The grooves can also be formed by means of rib-like extensions at the inner surface of the side walls, or by means of a laterally displaced arrangement of different side wall sections, or by other means known by a person skilled in the art.

In addition, at least two guide pegs are formed on the outside of the left side wall and on the outside of the left side wall, wherein the number of the guide pegs on the respective outsides being equal to the number of grooves formed in the side walls. These guide pegs are located approximately at the height of the bottom of the transport container to ensure a rigid connection to the bottom which is preferred for reasons of increased strength. The guide pegs are formed in such a way that the guide pegs of an upper transport container can be inserted through the groove openings into the grooves of a transport container underneath. The grooves are shaped so that the guide pegs of the upper transport container can slide into the grooves of the lower transport container downwards as far as the groove stops, when two transport containers are placed inside one another. Further, the outermost ends of the guide pegs may be provided with downwardly extending protrusions for engaging with an upwardly extending rib or with a channel formed at the upper surface of the side walls of a transport container underneath when both transport containers are stacked on top of one another. Thereby, it can be better prevented that two transport containers can inadvertently slide inside each other. Further, the upper surfaces (support surface) may be provided with suitable ribs for engaging with the downwardly extending protrusions of the guide pegs to ensure increased strength when placed inside one another.

In a first embodiment of the transport container of the present invention, in a horizontal direction, the distances between the guide pegs are different from the distances between the upper openings of the grooves. It is thus ensured that with horizontal position and vertical alignment of two transport containers situated on top of one another, i.e., the two transport containers are situated on top of one another in horizontal and parallel relationship, not all the guide pegs of the upper transport container can simultaneously penetrate into all the upper openings of the grooves of the lower transport container, thus preventing the upper transport container being unintentionally placed in the lower transport container. Instead, the groove openings and the guide pegs are arranged relative to each other in such a way that the upper transport container can only be placed inside the lower transport container by a type of plunging movement (condition of being one inside the other). To do this, the upper transport container is inclined in relation to the lower transport container about a horizontal axis extending transverse to both side walls, and the front (consequently lowest) guide peg is inserted into the front groove of the lower transport container and then being moved downwardly into the groove. In this way, the following guide peg is brought into alignment with the following groove opening and can be inserted into the appropriate groove by a continued plunging movement. If there are more than two grooves or guide pegs on each side of the transport containers, the third guide peg can then also be inserted into the third groove, and so on.

In this way, the guide pegs of the upper transport container can only be inserted one after the other into the appropriate grooves of the transport container underneath by means of the plunging movement as explained, until the guide pegs push against the appropriate groove stops of the corresponding grooves. It is clear that the distances between the guide pegs are equal to the distances between the groove stops to make it possible for the upper transport container to be placed inside the lower transport container in a horizontal position (i.e. a horizontal and parallel relationship of two transport containers one above the other).

In a second embodiment of the transport container of the present invention, in a horizontal direction the distances between the guide pegs can be equal to the distances between the upper openings of the grooves. In this second embodiment, at least three guide pegs are formed on the outer surface of the left side wall and on the outer surface of the right side wall, wherein the central guide peg (or the central guide pegs) is (are) shorter and preferably thicker than the outermost guide pegs. The horizontal cross sections of the grooves and the upper openings of the grooves, the number of which is equal to the number of the guide pegs, correspond to the shape of the respective guide pegs. This means that the groove openings and the grooves are formed in such a way that the outermost guide pegs can only received in the outermost groove openings and grooves, and that the inner (central) guide pegs can only be received in the inner (central) groove openings and grooves. In other words, the outermost groove openings and grooves are deeper and narrower (more slim) for being able to receive the longer and preferably thinner outermost guide pegs, and the central groove openings and grooves are more shallow and preferably wider for being able to receive the shorter and preferably thicker central guide pegs. Of course, the central guide pegs can be longer and/or thinner than the outermost guide pegs, wherein the respective groove openings and grooves have a corresponding shape. It is noted that other groove shapes and guide peg shapes are possible. However, it is important that the different grooves and guide pegs are formed in such a way that the outermost guide pegs can only be inserted in the outermost grooves and, preferably, the inner guide pegs can only be inserted in the inner grooves. Further, it is noted that the shape and arrangement of the grooves and the guide pegs is symmetrically.

By means of the above features it is thus ensured that, when two transport containers according to the second embodiment of the invention are situated on top of one another, the guide pegs of the upper transport container can only penetrate into all the upper groove openings and grooves of the lower transport container when the guide pegs of the upper transport container are in alignment with the corresponding groove openings of the lower transport container. Thus, when an upper transport container is pushed over the lower transport container for being stacked on top of the lower transport container, the front guide peg in pushing direction of the upper transport container can not unintentionally penetrate, because of its longer shape, into a central shallow groove opening. In the same way, a central thick guide peg can not unintentionally penetrate into one of the outermost narrow grooves. Therefore, it is prevented that the guide pegs of the upper transport container can penetrate into the wrong upper groove openings of the lower transport container, thus preventing the upper transport container unintentionally being placed in the lower transport container when the upper transport container being pushed over the lower transport container. Consequently, when an upper transport container according to the second embodiment of the invention is, for the purpose of stacking, pushed over a lower transport container, the front (in pushing direction) longer guide pegs slide over the central shallow groove openings of the lower transport container without penetrating into these groove openings. When the front (outermost) longer guide pegs of the upper transport container are in alignment with the corresponding front (outermost) deeper groove openings of the lower transport container, then also all other guide pegs of the upper transport container are in alignment with the corresponding groove openings of the lower container, and all guide pegs simultaneously can penetrate into the corresponding grooves such that the upper transport container can be inserted into the lower transport container. It is obvious that the upper transport container can be inserted into the lower transport container without the plunging movement as described above. When the guide pegs of the upper transport container are in alignment with the groove openings of the lower transport container, then the upper transport container can be inserted with a vertical or diagonal movement in a downward direction, whereby the guide pegs of the upper transport container simultaneously slide into the grooves of the lower transport container, which is advantageous for automatic stacking and unstacking. It is obvious that the described shape and structure of the grooves and guide pegs can also be used in the first embodiment.

In addition, in both embodiments of the transport container of the invention, recesses are preferably made in the upper edges (i.e. of the rail) of the right side wall and the left side wall, so that the guide pegs of an upper transport container can engage with the recesses of a transport container underneath (stacked condition), so that the two transport containers thus stacked on top of one another cannot be displaced relative to each other. To enable the guide pegs of the upper transport container to engage with the recesses of the lower transport container, the distances between the recesses must be equal to the distances between the guide pegs. As described above, when the outermost ends of the guide pegs are provided with downwardly extending protrusions for engaging with an upwardly extending rib or with a channel formed at the upper surface of the side walls of a transport container underneath when both transport containers are stacked on top of one another, then, preferably the recesses are also provided with such a rip or channel to prevent that the guide pegs inadvertently slide away towards the inner space of the transport container and to prevent the two transport containers can be inadvertently placed inside each other.

In the second embodiment of the transport container of the invention, the cross sections of the recesses correspond to the cross sections of the corresponding guide pegs so that, for example, an outermost longer guide peg of the upper transport container can not penetrate into a central shallow recess. As already mentioned above, also in the second embodiment the protrusions at the guide pegs and the rip or channels can be provided.

In the second embodiment, when an upper transport container is pushed over the transport container underneath for being stacked on top thereof, the front guide peg in pushing direction of the upper transport container can not unintentionally penetrate, because of its longer shape, into in central shallow groove opening or into a central shallow recess. In the same way, a central thick guide peg can not unintentionally penetrate into an outermost narrow groove or into an outermost narrow recess. Therefore, it is prevented that the guide pegs of the upper transport container can penetrate into the wrong recesses of the lower transport container, thus preventing the guide pegs of the upper transport container can penetrate into the wrong recesses of the lower transport container, therefore, interlocking of the guide pegs of the upper transport container with the wrong recesses of the transport container underneath is prevented when the upper transport container being pushed over the lower transport container. Consequently, when an upper transport container according to the second embodiment of the invention is, for the purpose of stacking, pushed over a transport container underneath, the front (in pushing direction) longer guide pegs slide over the central shallow groove openings of the lower transport container without penetrating into the central groove openings. When the front (outermost) longer guide pegs of the upper transport container are in alignment with the corresponding front (outermost) deeper recesses of the lower transport container, then all other guide pegs of the upper transport container are also in alignment with the corresponding recesses of the lower transport container, and all guide pegs can simultaneously penetrate into the corresponding recesses such that the upper transport container can be stacked on top of the lower transport container.

Preferably, in both embodiments the dimensions and designs of the bottom and of the guide pegs are preferably to be selected so that a transport container according to the invention can be stacked on top of a known baker's tray, with the bottom and the guide pegs of an upper transport container according to the invention engaging properly with the rail of a lower baker's tray. The upper edges of the side walls and the front and rear wall of the transport container according to the invention are dimensioned so that they engage with the peripheral edge of the bottom and with the projections on the underside of the bottom of an upper baker's tray. In this design the transport container according to the invention is compatible with the known baker's tray and a combination of these can be stacked on top of one another; however it is not possible for the transport containers and baker's trays to be placed inside one another. Preferably, at the outer areas of the corners of the upper surface of the rail protrusions or upward ribs are provided, thus preventing an upper baker's tray can slide along the rail of a lower transport container according to the invention. In particular, this is important for transport containers according to the invention which have a front wall and/or rear wall which is lower in height.

In both embodiments of the transport container according to the invention, four grooves, four recesses and four guide pegs are preferably formed on each side wall. According to the above considerations, the grooves are at an angle to the vertical, are slightly bent, and each have a different slope and configuration. The exact configuration, slope and curve of the grooves from the groove openings at the upper edge of the side walls down to the groove stops depends on the desired nature of the plunge movement, the number of and the distances between the guide pegs.

In the first embodiment of the transport container according to the invention, the grooves in one side wall each have a different slope, curve and configuration, with the corresponding opposite grooves in the other side wall are identical, respectively. In other words, the grooves in one side wall all have a different shape, with the side walls are identical and mirror symmetrical. The precise configuration, slope and curve of the grooves from the groove opening in the upper edge (rail) of the side walls to the groove stop depends on the desired nature of the plunge movement, the number of and the distances between the guide pegs etc.

In the second embodiment of the transport container according to the invention, the grooves are also at an angle to the vertical, however, the grooves substantially have the same shape and orientation. The precise shape, slope and curve of the grooves from the groove opening in the upper edge (rail) of the side walls to the groove stop depends on the number of and the distance between the guide pegs and the groove openings. Preferably, the lower groove stops of a groove, the above corresponding recesses and the guide pegs are in vertical alignment to each other.

The essential advantage of the transport container according to the invention consequently relates to the special shape and arrangement of the grooves/slits and the guide pegs ensuring safe stacking of the transport containers filled with product on top of one another, and at the same time prevents the transport containers inadvertently being placed inside one another when being stacked on top of one another or being placed inside one another in a wrong orientation/alignment.

A further essential advantage of the transport container according to the invention consists in the fact that the guide pegs are reinforced by means of ribs, wherein the guide pegs are formed with rib-shaped extensions which extend towards the grooves. It is also possible that the grooves are formed by channels at the inner surface of the side walls, wherein the walls of the channels provide reinforcement ribs at the outer surface of the side walls, and wherein the thickness of the material of the channels at at least some portions thereof is higher than at the remaining wall portions. By these measures, reinforcement ribs are provided which substantially have the shape of the grooves. The sidewalls can be inclined to allow improved engagement of the grooves of a lower container with the guide pegs of an upper container. Further, the thickness of said ribs at or near the guide pegs can be higher and, thereafter, the thickness decreases. The advantage of this configuration is an essentially higher strength of the guide pegs and, therefore, use of less expensive and less rigid materials or a decreased wall thickness with the same material is possible to reduce the weight of the container.

When a plunge movement inside one another or a take out movement in only one direction has to realized, a symmetrical arrangement of the guide pegs is not necessary. It is therefore possible to provide the transport containers with only two or three guide pegs and grooves at each side wall (the use of four or more guide pegs is also possible, of course). This makes the transport container less complex and easier to produce.

When using two guide pegs and two grooves at each side of the container, the packing personnel immediately realizes the correct direction of the plunge movement. Further, a plunge movement in wrong direction is prevented, first, by the different distances of the guide pegs and the grooves and, second, by the reinforcement ribs which extend in the direction of the grooves. When three or more guide pegs are used, the distances of the guide pegs must not be symmetrical; for example, the distances can increase, seen in one direction.

A further important feature is the provision of a guide groove formed at the upper surface of the rail, with slide ribs formed at the guide pegs of a respective upper transport container can slide within said guide groove. This is, in the upper support surface of the rail of each of the side walls, a groove having a V-shaped cross-section is provided, wherein the outermost inner surface of said groove substantially extends in vertical direction, and the innermost inner surface is slanted. At the bottom surface of the guide pegs, slide ribs having a corresponding cross-section are formed. This configuration has the advantage that, when two transport containers being stacked one above the other, the inwardly directed and slanted surface of the guide ribs at the guide pegs of the upper container abuts against the also slanted and outwardly directed surface of the guide groove, whereby, in case of loading (the upper container is filled with products), the side walls of the lower container are pushed together. Therefore, it is possible, without any problems, that more that 15 transport containers filled with products being stacked one above the other, without the side walls of the transport container underneath, which are slightly slanted in outward direction, being push away from each other. This is a very important feature, in particular in case of heat influence when the products within the containers are dried.

In case of containers being provided with three or more (for example four) guide pegs and grooves, it is preferred that the central guide peg(s) are arranged somewhat deeper compared to both outer guide pegs such that only the central guide pegs slide in the above described rail, wherein these guide pegs are formed with the above described tapered slide ribs which slide within the correspondingly formed guide groove to achieve the side walls to be pushed together and to prevent the side walls to be pushed away from each other, in case of a force applied from above.

A further advantage of the transport container according to the invention consists in the fact that a good ratio of filled volume:empty volume is achieved. This means that the volume of transport containers stacked on top of one another compared with the volume of transport containers placed inside one another is relatively large. This good filled:empty ratio preferably amounts to 2:1 or better and is achieved in that the side walls and the front or rear wall of the transport container according to the invention are only slightly inclined relative to the vertical, which means that the transport container according to the invention has a very large filled volume. The formation of slits/grooves in the side walls however at the same time means that the transport containers can be placed deep inside each other.

Yet another advantage of the transport container according to the invention consists in the fact that there are no movable parts which can break. In addition the transport container according to the invention is compatible with other transport containers.

Finally the transport container according to the invention is easy to clean.

Preferred forms of construction of the invention are now described with reference to the attached drawings; these show:

FIG. 1 a diagrammatic perspective view of a first form of construction of the first embodiment of the stackable/nesting transport container according to the invention, with the shape of the grooves is shown in a diagrammatic way;

FIG. 2 a diagrammatic perspective view of a second form of construction of the first embodiment of the stackable/nesting transport container according to the invention, with the shape of the grooves is shown in a diagrammatic way;

FIG. 3 a diagrammatic front view of two transport containers according to the invention from FIG. 2, represented stacked one on top of the other;

FIG. 4 a diagrammatic side view of two transport containers according to the invention from FIG. 2, arranged one above the other with space between;

FIG. 5 a diagrammatic side view of two transport containers according to the invention, arranged one above the other with space between but slightly offset against each other;

FIG. 6 a diagrammatic side view, similar to FIGS. 4 and 5, of two transport containers according to the invention arranged one above the other with space between and in opposite orientation compared to FIGS. 4 and 5, with the grooves formed in the side walls of the transport containers arranged in opposite orientation;

FIG. 7 a diagrammatic side view of two transport containers according to the invention in opposite orientation, arranged one inside the other, with the grooves formed in the side walls of the transport container arranged in opposite orientation;

FIG. 8 a view, similar to FIG. 7, but with the grooves formed in the side walls arranged in the same orientation;

FIG. 9 a diagrammatic side view of four transport containers according to the invention, arranged one inside the others with the grooves formed in the side walls of the lower three transport containers arranged in the same orientation;

FIG. 10 a diagrammatic side view of five transport containers according to the invention, arranged one inside the other, with the grooves formed in the side walls of the transport containers arranged in different orientations;

FIG. 11 a diagrammatic representation showing the progressive insertion of an upper transport container into a transport container underneath;

FIG. 12 a diagrammatic representation of how the external (outermost) guide pegs of an upper container are inserted step by step into the grooves of a transport container underneath, to place the upper transport container inside the lower transport container;

FIG. 13 a diagrammatic representation of a third form of construction of the first embodiment of the transport container according to the invention, in which the front wall and the rear wall are lower in height than the side walls;

FIG. 14 a diagrammatic representation of a form of construction of the second embodiment of the transport container according to the invention;

FIG. 15 a a top view of the transport container from FIG. 14;

FIG. 15 b a front view of the transport container from FIG. 14;

FIG. 15 c a side view of the transport container from FIG. 14, with the groove having different shapes;

FIG. 15 d a detailed area of the front view of FIG. 14 in enlarged scale;

FIG. 16 a diagrammatic representation of a third embodiment of a transport container according to the invention, in which the side walls, the front wall and the rear wall have a step-like configuration;

FIGS. 17 a and 17 b a diagrammatic top view and cross sectional view of the central and outermost guide pegs;

FIG. 18 a diagrammatic cross sectional view of a side wall of the transport container from FIG. 16;

FIG. 19 a diagrammatic and not in correct scale of the transport container shown in FIG. 16 in which the shape of the grooves and guide pegs formed at the side walls are shown, as well as a diagrammatic cross sectional view along line A-A showing the structure of the grooves in the side walls;

FIGS. 20 a and 20 b a diagrammatic view of a transport container according to another preferred embodiment of the present invention;

FIGS. 21 a and 21 b a diagrammatic view of a transport container according to a modification of the embodiment from FIGS. 20 a and 20 b of the present invention;

FIGS. 22 a and 22 b a diagrammatic view of a transport container according to a modification of the embodiment from FIGS. 20 a, 20 b, 21 a and 21 b of the present invention; and

FIG. 23 a diagrammatic view of a preferred embodiment of the guide peg and the guide groove.

FIG. 1 shows a perspective representation of a first form of construction of the first embodiment of the stackable/nesting transport container 1 according to the invention. The transport container 1 has a bottom 2 that may be a continuous surface which may as an option have crosspieces underneath to increase the stability of the bottom. Alternatively, however the bottom 2 can also be perforated or have a cellular structure. The bottom 2 is preferably rectangular, but may also have rounded or differently shaped corners. From the bottom 2 of the transport container 1 a front wall 3, a rear wall 4, a left side wall 5 and a right side wall 6 extend to form a receptacle open towards the top. The bottom 2, the front wall 3, the rear wall 4, the left side wall 5 and the right side wall 6 are preferably made from plastic, although other materials can be used. The front wall 3, the rear wall 4, the left side wall 5 and the right side wall 6 are preferably inclined slightly outwards, to enable individual transport containers 1 to be placed one inside the other.

In the inner surface of the left side wall 5 four grooves 7 a, 7 b, 7 c and 7 d are formed, which are inclined relative to the vertical. In the inner surface of the right side wall 6 corresponding grooves 8 a, 8 b, 8 c and 8 d are formed, that are inclined to the vertical in the same arrangement as the grooves 7 a, 7 b, 7 c and 7 d in the inner surface of the left side wall 5. The grooves 7 a-7 d and 8 a-8 d are shown in a diagrammatic representation; the special way in which these individual grooves are inclined will be described in detail below.

On the upper edge of the front wall 3, the rear wall 4, the left side wall 5 and the right side wall 6 there is a broad circumferential edge/rail 9, which preferably has a rectangular cross-section. Alternatively it is possible that only the upper edges of the left side wall 5 and the right side wall 6 are formed with such a rail 9 or such a broad edge. The rail 9 on the upper edge of front wall 3 and rear wall 4 serves preferably to increase the stability of the transport container 1.

As can be clearly seen in FIG. 1, the grooves 7 a-7 d of the left side wall 5 and the grooves 8 a-8 d of the right side wall 6 extend upwards to the upper surface of the rail 9 and are closed at bottom, forming groove stops 10 a-10 d at the lower end of grooves 7 a-7 d and groove stops 11 a-11 d (not shown) at the lower end of grooves 8 a-8 d. The groove stops 10 a-10 d and 11 a-11 d all lay in one horizontal plane.

On the outer surface of the left side wall 5 there are four guide pegs 12 a-12 d (not shown), and on the outer surface of the right side wall 6 there are four guide pegs 13 a-13 d. These guide pegs are preferably formed in the lower area of the outer surface of the side walls at the level of the bottom or just above it, and also all lie in one horizontal plane. The guide pegs preferably have a round cross-section but can also have a polygonal cross-section, extend in a horizontal direction and are preferably rounded off at their outer ends. In addition, on the outer surface of the left side wall 5, at its ends near to the front wall 3 and rear wall 4 respectively, at the level of the bottom 2 there are retaining pegs 14 a, 14 b (not shown), and on the outer surface of the right side wall 6, at its ends near to the front wall 3 and rear wall 4 respectively, at the level of the bottom 2 there are also retaining pegs 15 a, 15 b.

In the upper surface of the rail 9 of the left side wall S and the right side wall 6 there are also four recesses 16 a-16 d and 17 a-17 d respectively. The recesses preferably have a semi-circular cross-section or a cross-section that matches the cross-section of the guide pegs.. The function of the grooves, guide pegs and recesses is described in detail below.

FIG. 2 shows a second form of the first embodiment of the stackable/nesting transport container 20, with the same reference numbers being used to designate the same elements in both figures.

The essential difference between the stackable transport container 1 of the first form of construction from FIG. 1 and the stackable transport container 20 of the second form of construction from FIG. 2 consists in the fact that the grooves 7 a-7 d in the left side wall 5 and the grooves 8 a-8 d in the right side wall 6 extend completely through the side walls, thus forming slits or cuts. In the description of the following FIGS. 3 to 13, reference will still be made to grooves, both with respect to the grooves in these figures that do not go through the wall, as in FIG. 1, and also grooves that do go through the wall, as in FIG. 2. The advantage of the grooves going through the wall (slits) is that the material of the side walls can be thinner and the side walls do not need to be so sharply inclined. If for example it is necessary for the transport container to form a watertight trough, then it is necessary to use grooves that do not go through the walls.

FIG. 13 shows a third form of construction of the transport container 30 according to the invention. The only difference between this container and the transport containers from FIGS. 1 and 2 is that the front wall 3 and the rear wall 4 are smaller in height than the side walls 5 and 6. The advantage of this shortened side or rear wall 3, 4 consists in the fact that the transport containers can nest deeper inside one another. The grooves can have a form as in FIG. 1 or in FIG. 2.

As is further to be seen in FIG. 2, the grooves 7 a-7 d and 8 a-8 d do not go through at the level of the rail 9, so that an outer section of the rail 9 remains in the area of the grooves, to increase the stability of the transport container 20. Otherwise, the construction of the transport container 20 is similar to that of the transport container 1. In the front wall 3 and the rear wall 4, there may preferably be openings 18, 19 which are designed to make it easier to grasp and carry the container 20 with the hands. Further, there may be additional openings in the side wall below the groove or between the grooves. The openings in the front wall, the rear wall and/or both side walls can however also be provided in the transport containers of FIGS. 1 and 13.

FIG. 3 shows a front view of two transport containers 20′, 20″ that are stacked one on top of the other. This stacking arrangement, with one container on top of the other, is preferred when the transport containers are filled with product. As FIG. 3 clearly shows, the guide pegs 12 a-d on the left side wall 5 of the upper transport container 20′ rest in the recesses 16 a-d, which are formed in the rail 9 of the lower transport container 20″. Similarly, the guide pegs 13 a-d formed on the right side wall 6 of the upper transport container 20′ rest in the recesses 17 a-d, which are formed in the rail 9 of the lower transport container 20″. This ensures that the transport container 20′ will not slip out of place relative to the lower transport container 20″. In the same way further transport containers 20 can be stacked on top of the upper transport container 20′.

It is clear that the distances between the individual guide pegs 12 a-d and 13 a-d respectively are in each case equal to the distances between the corresponding recesses 16 a-d and 17 a-d respectively. It is further clear that because of the method of representation in FIG. 3 only the front guide pegs 12 a and 13 a, and the front recesses 16 a and 17 a can be seen.

FIG. 4 shows a side view of two transport containers 20′ and 20″, positioned one above the other, in order to be stacked one on top of the other. However for clarity of representation, the rail 9 on both the transport containers 20′, 20″ has been omitted. FIG. 4 clearly shows that the guide pegs 13 a-d on the visible right side wall 6 of the upper transport container 20′ in each case have the same distance between them as the associated recesses 17 a-d of the transport container 20″ underneath. The same of course also applies to the distances between the guide pegs 12 a-d on the left side wall 5 (not shown) of the upper container 20′ and the distances between the corresponding recesses 16 a-d in the upper edge of the left side wall 5 of the transport container 20″ underneath. In this way it can be ensured that in the stacked position all the guide pegs 12 a-d and 13 a-d of the upper transport container 20′ can engage directly with the corresponding 16 a-d and 17 a-d respectively, of the transport container 20″ underneath, when the upper transport container 20′ and the lower transport container 20″ are situated in precise vertical alignment relative to one another.

The distance between the guide pegs 13 a and 13 b is preferably equal to the distance between the guide pegs 13 c and 13 d; this distance is preferably not the same as the distance between the guide pegs 13 b and 13 c. The same applies to the guide pegs 12 a-12 d on the left side wall of the transport container. The distances between the recesses 16 a-d and 17 a-d respectively are corresponding. Consequently the distances between the guide pegs and the recesses are designed to be in mirror symmetry to each other. In this way two or more guide pegs can only engage with the associated recesses if the upper transport container is placed in precise vertical alignment to the lower transport container. This means that the upper transport container can be pushed more easily onto the lower transport container, without the guide pegs being able to engage with the wrong recesses during the pushing movement. If, when being pushed on, a guide peg is in alignment with the wrong recess, it cannot however engage with this recess, as the upper transport container will be held on the upper edge of the rail by the other guide pegs that because of the different distances explained above cannot be in alignment with the recesses underneath. Only when all the guide pegs of the upper transport container are in alignment with all the corresponding recesses of the lower transport container can the upper transport container be lowered, which means that all the guide pegs of the upper transport container engage simultaneously with the appropriate recesses of the lower transport container.

FIGS. 1-13 show the transport containers each with four guide pegs, four recesses and four grooves on each side of the transport container. The distance between the guide pegs 12 a and 12 b (and 13 a and 13 b) is equal to the distance between the guide pegs 12 c and 12 d (and 13 c and 13 d), for example 15 cm. The distance between the guide pegs 12 b and 12 c (and 13 b and 13 c) is different and amounts, for example, to 20 cm. The distances between the associated recesses are corresponding. Consequently the distances between the guide pegs and the recesses are in mirror symmetry to each other. It is clear that it is also possible to have a different number of guide pegs, recesses and grooves. Thus for example it is possible to have two, three or more than four guide pegs, recesses and grooves respectively on each side of the transport container according to the invention. With regard to the distance between the guide pegs and the recesses it is only important that the guide pegs of the upper transport container engage with the recesses in the lower transport container, when the two transport containers are in the stacking position relative to one another. It is moreover important that the distances between the guide pegs and the recesses respectively are in each case selected so that the guide pegs of the upper transport container engage with the recesses of the lower transport container in both alignments of the transport container to each other, i.e. in the alignment shown in FIG. 4 and in the alignment turned round 180° (see FIG. 6), if both transport containers are stacked on top of one another in the correct position relative to each other.

As is also shown clearly by FIG. 4, the distances between the lower groove stops 11 a-d are equal to the distances between the associated guide pegs 13 a-d. Preferably, the groove stops 11 a-d are in vertical alignment with the associated guide pegs 13 a-d. The same also of course applies to the groove stops 10 a-d and the guide pegs 12 a-d on the left side wall 5 (not shown) of the transport container. It is clear that these conditions also apply to a transport container that has a different number of guide pegs and grooves, as explained above.

FIG. 4 also shows that the distances between the upper openings of the grooves 7 a-d and 8 a-d differ from the distances between the associated guide pegs 12 a-d and 13 a-d respectively. This prevents the guide pegs 12 a-d and 13 a-d respectively, when the lower transport container 20″ and the upper transport container 20′ are each placed in a horizontal position, from all becoming vertically aligned with one another. If the upper transport container 20′ in FIG. 4 is pushed from left to right in a horizontal position onto the transport container 20″ underneath, in each case only one or two of the guide pegs 12 a-d and 13 a-d on the left side wall 5 and on the right side wall 6 respectively, of the upper transport container 20′ can come into alignment with an upper opening of the grooves 7 a-d and 8 a-d of the left side wall 5 and the right side wall 6 respectively, of the lower transport containers 20″; the other guide pegs slide on the upper edge of the rail. This ensures that the upper transport container 20′, when pushed from left to right on the transport container 20″ underneath, so that the guide pegs 12 a-d and 13 a-d slide along the upper edge of the rail 9, cannot inadvertently get into the nesting position in relation to the lower transport container 20″, as the guide pegs 12 a-d and 13 a-d cannot all simultaneously come into alignment with the upper openings of the grooves 7 a-d and 8 a-d respectively, and thus cannot all simultaneously slip into the grooves 7 a-d and 8 a-d respectively. The way in which the upper transport container 20′ can be brought to nest inside the lower transport container 20″ is described in detail below.

FIG. 5 shows in detail how the upper transport container 20′ is pushed onto the lower transport container 20″ with reference to FIG. 4. As can be seen in FIG. 5, the right guide peg 13 d on the right side wall 6 of the upper transport container 20′ is located in alignment with the upper opening of the groove 8 d in the right side wall 6 of the lower transport container 20″ and could easily slide into the groove 8 d by virtue of its own weight. However this is prevented by the fact that the other three guide pegs 13 a, b and c on the right side wall 6 of the upper transport container 20′ are not in alignment with the upper openings of their associated grooves 8 a, 8 b and 8 c in the right side wall 6 of the lower transport container 20″, but instead are held and supported on the upper edge/rail 9 or the right side wall 6 of the lower transport container 20″. If the upper transport container 20′ is pushed still further to the right, the guide peg 13 d of the upper transport container 20′ comes to rest on the upper edge of the rail 9 of the right side wall 6 of the lower transport container 20″, the guide peg 13 c of the upper transport container 20′ comes into alignment with the upper opening of the groove 8 c of the lower transport container 20″, whilst the guide pegs 13 a and 13 b of the upper transport container 20′ come to rest on the upper edge of the rail 9 of the right side wall 6 of the lower transport container 20″. As already explained above, the distances between the guide pegs of the upper transport containers and the distances between the recesses in the lower transport container 20″ are preferably selected so that the guide pegs of the upper transport container 20′ only engage with the recesses of the lower transport container 20″, when all four guide pegs of the upper transport container 20′ are in vertical alignment with the associated four recesses of the lower transport container 20″. In this case it cannot happen that during the pushing of the upper transport container 20′ onto the lower transport container 20″, for example three guide pegs 13 b, c and d of the upper transport container engage with the recesses 17 a, b and c of the lower transport container. This considerably simplifies the pushing of the upper transport container 20′ onto the lower transport container 20″.

It is clear that the above considerations, which because of the representation in FIGS. 5 and 6 relate in each case to the right side walls 5 of the upper transport container 20′, and the lower transport container 20″, also apply in each case to the left side walls 6 of the upper transport container 20′ and the lower transport container 20″, as the transport containers have a symmetrical construction in each case.

FIG. 6 is a representation, similar to that in FIGS. 4 and 5, in which the alignment of the grooves of the upper transport container 20′ (which are directed from the right at the bottom to the left at the top) differs from the alignment of the grooves of the lower transport container 20″ (which are directed from the left at the bottom to the right at the top). It can also be seen here that the guide pegs of the upper transport container are in alignment with the associated recesses of the lower transport container. The considerations relating to FIG. 5 on the pushing of the upper transport container 20′ onto the lower transport container 20″ also of course apply to the orientation of the two transport containers 20′, 20″ shown in FIG. 6.

FIG. 7 shows the case in which the upper transport container 20′ is nesting inside the lower transport container 20″. Here it can be seen that the distances between the guide pegs 13 a-d of the upper transport container are equal to the distances between the groove stops 11 a-d of the lower transport container 20″, so that the guide pegs of the upper transport container 20′, sit precisely in the lower closed end of the grooves 8 a-d of the lower transport container 20″, and fit precisely against the groove stops 11 a-d of the lower transport container 20″. FIG. 7 shows the case in which the alignment of the grooves of the upper transport container 20′ is different from the alignment of the grooves of the lower transport container 20″.

FIG. 8 shows the case in which the upper transport container 20′ is nesting inside the lower transport container 20″. Here the grooves of the upper transport container are in the same alignment as the grooves of the lower transport container, as this is also shown in FIGS. 4 and 5. In this case also, the guide pegs of the upper transport container 20′ engage precisely with the groove stops of the lower transport container 20″.

FIGS. 9 and 10 show several transport containers nesting one inside the other, with the orientation of these transport containers differing from one another. It is clearly shown that it is completely immaterial, in which orientation the transport containers are placed one inside the other. Unlike some transport containers according to the state of the art, with the transport container according to the invention, no rotation around 180° is necessary; in addition no movable parts are necessary.

FIG. 11 shows schematically how the upper transport container 20′ can be placed inside the lower transport container 20″. The following description again relates only to the right side wall 6 of the upper transport container 20′ or the lower transport container 20″ respectively, but it is of course clear that these considerations also apply in each case to the left side walls 5 of the upper transport container 20′ and the lower transport container 20″, or the associated grooves, groove stops and guide pegs, which are arranged on the left side wall 5 of the upper/lower transport container 20′, 20″.

It can be seen that the upper transport container 20′ is placed inside the lower transport container 20″ in a position sloping downwards. First of all the front guide pegs (FIG. 11 shows only the right guide peg 13 d of the upper transport container) are inserted into the upper openings of the front groove 8 d into the groove 8 d of the lower transport container. Because of the sloping position of the upper transport container 20′ relative to the lower transport container 20″, if the front guide peg 13 a of the upper container 20′ is pushed deeply enough into the front groove 8 a of the lower transport container, the guide peg 13 c can also be inserted through the upper opening of the second groove 8 c into this groove 8 c of the lower transport container. If the guide pegs 13 d and 13 c of the upper transport container 20′ are pushed further into their associated grooves 8 d and 8 c, then the guide peg 13 b of the upper transport container 20′ comes into alignment with the groove 8 b of the lower transport container 20″ and can be pushed into it. If the upper transport container 20′ is inserted further, at some point the guide peg 13 a of the upper transport container 20′ engages with the groove 8 a of the lower transport container 20″ and can be pushed into it.

It is clear that the upper transport container 20′ can only be placed inside the lower transport container 20″ by means of a kind of plunging movement. As explained above, the upper transport container cannot thus be inadvertently pushed into the lower transport container, preventing the produce inside the lower transport container from being inadvertently damaged.

FIG. 12 once again shows the plunging movement of the upper transport container into the lower transport container, but with the outline of the upper transport container omitted, to enable the progressive movement of the guide pegs of the upper transport container into the grooves of the lower transport container to be represented better.

This way of plunging the upper transport container 20′ into the lower transport container 20″ also results in increased stability. It also guarantees that transport containers placed one inside the other can be unstacked without difficulty. As already mentioned, the guide pegs are slightly beveled, which makes it easier to push the guide pegs into the grooves and also facilitates unstacking (manually or automatically).

FIG. 14 shows a form of construction of the stackable/nesting transport container 40 according to the second embodiment of the invention. The difference relative to the transport containers according to the first embodiment from FIGS. 1, 2 and 13 consists in the fact that the grooves 7 a-7 d in the left side wall 5 and the grooves 8 a-8 d in the right side wall 6 extend at an angle to the vertical and have in general all the same shape.

On the upper edge of the front wall 3, the rear wall 4, the left side wall 5 and the right side wall 6 there is a edge/rail 9. The front wall 3 is lower in height than the other three walls. The rail 9 on the upper edge of front wall 3 and rear wall 4 serves preferably to increase the stability of the transport container 40.

As can be clearly seen in FIG. 14, the grooves 7 a-7 d of the left side wall 5 and the grooves 8 a-8 d of the right side wall 6 extend upwards to the upper surface of the rail 9 and are closed at bottom, forming groove stops at the lower end of grooves.

On the outer surface of the left side wall 5 there are four guide pegs 12 a-12 d (not shown), and on the outer surface of the right side wall 6 there are four guide pegs 13 a-13 d. The guide pegs preferably have a round cross-section but can also have a polygonal cross-section, extend in a horizontal direction and are preferably rounded off at their outer ends. The two outermost guide pegs 12 a, 12 d and 13 a, 13 b respectively at the left side wall and at the right side wall are longer and thinner than the central guide pegs 12 b, 12 c and 13 b, 13 c respectively at the left side wall and the right side wall 5, 6.

In the upper surface of the rail 9 of the left side wall 5 and the right side wall 6 there are also four recesses 16 a-16 d and 17 a-17 d respectively. The recesses preferably have a semi-circular cross-section or a cross-section that matches the cross-section of the guide pegs. As can be clearly seen in FIG. 14, the outermost recesses 16 a, 16 d and 17 a, 17 d respectively are deeper and have a smaller diameter for being able to receive the corresponding outermost guide pegs 12 a, 12 d and 13 a, 13 d respectively. Accordingly, the central recesses 16 b, 16 c and 17 b, 17 c respectively are shallower and have a larger diameter for being able to receive the corresponding central guide pegs 12 b, 12 c and 13 b, 13 c respectively.

In a similar way, the openings of the grooves are shaped to correspond to the shape and dimensions of the respective guide pegs 12 a-d and 13 a-13 d. As can be clearly seen in FIG. 14, the openings of the outermost grooves 7 a, 7 d and 8 a, 8 d respectively are deeper and narrower for being able to receive the respective longer and thinner outermost guide pegs 12 a, 12 d and 13 a, 13 d respectively. Further, the openings of the central grooves 7 b, 7 c and 8 b, 8 c respectively are more shallow and wide for being able to receive the shorter and thicker central guide pegs 12 b, 12 c and 13 b, 13 c respectively.

It is obvious that, when an upper transport container 40 is pushed over a lower transport container 40 in pushing direction, the front outermost longer guide pegs 12 d and 13 d slide over the central more shallow groove openings 16 b, 16 c and 17 b, 17 c respectively and over the openings of the central grooves 7 b, 7 c and 8 b, 8 c respectively and can only penetrate into the outermost deeper and more shallow recesses 16 d and 17 d respectively or into the outermost deeper and more shallow grooves 7 d and 8 d respectively.

In FIG. 14, it can also be seen that at the upper surface of the rail 9 (preferably at the outer corners thereof) upward ribs 50 a, 50 c and 50 d are provided. These ribs are arranged to engage with the outer edge of the bottom of a known baker's tray stacked on top of the transport container 40 according to the invention. In particular, these ribs 50 a, 50 c and 50 d are important for the transport container 40 which has a front wall 3 and/or rear wall 4 which is lower in height than the side walls 5, 6 and when the projections on the underside of the bottom of the known upper baker's tray do not engage with the rail of the front wall and/or rear wall of the transport container underneath of the invention. In this case, the ribs 50 a, 50 c and 50 d engage with the outer edge of the bottom of the baker's tray thus preventing that the baker's tray can slide off the rail 9 of the transport container 40 underneath in forward or rearward direction. It is obvious that the ribs 50 a, 50 c and 50 d can also be provided at the respective forms of construction of the transport containers 1, 20 and 40 of first embodiment of the invention.

FIG. 15 a shows a top view of the transport container 40 of the second form of construction according to the invention. FIGS. 15 b and 15 c show a front view and a side view, respectively, of the transport container 40 from FIG. 15 a, which is provided with grooves as used in the first form of construction, however. FIG. 15 d shows a detail of the front view from FIG. 15 b in enlarged scale, to better represent the dimensions of the guide pegs.

FIG. 16 shows a perspective representation of a third and most preferred form of construction of the first embodiment of the stackable/nesting transport container 50 according to the invention. This transport container 50 has a bottom 2 that may be a continuous surface that may as an option have crosspieces underneath to increase the stability of the bottom. Alternatively, however the bottom 2 can also be perforated or have a cellular structure. The bottom 2 is preferably rectangular, but may also have rounded or differently shaped corners. From the bottom 2 of the transport container 50 a front wall 3, a rear wall 4, a left side wall 5 and a right side wall 6 extend to form a receptacle open towards the top. The bottom 2, the front wall 3, the rear wall 4, the left side wall 5 and the right side wall 6 are preferably made from plastic, although other materials can be used. The front wall 3, the rear wall 4, the left side wall 5 and the right side wall 6 each have a substantially vertically extending lower wall portion 103, 104, 105 and 106, and a substantially vertically extending upper wall portion 203, 204, 205 and 206. As can be seen in FIG. 16, the lower wall portions 103 -106 extend more inwardly, and the upper wall portions 203-206 extend more outwardly, so that the horizontal cross section plane extending between the lower wall portions is smaller than the horizontal cross section plane extending between the upper wall portions. The lower and upper wall portions are connected by means of a slightly inclined outwardly extending connecting portion 207 which extends inclined outwardly and upwardly from the upper edge of the lower wall portions to the lower edge of the upper wall portions. Substantially at the level of the connecting portion 207, an outwardly extending horizontal flange (303 and 306 in FIGS. 18 and 19) is formed at the outer surface of the side walls and, if desired, at the front wall and/of the rear wall. When two transport containers are placed inside one another, the downward surface of the flange 303, 306 of the upper transport container lies on the upward surface of the upper wall portions of the side walls and, if present, of the front wall and/of the rear wall of the transport container underneath. By means of such a construction, the stability of the stack is increased and the load of the guide pegs of the upper transport container supported on the groove stops of the transport container underneath is reduced.

The transport container 50 shown in FIG. 16 preferably has a total length of about 60 cm and a total width of about 40 cm, wherein the lower wall portions 103-106 preferably have a height of about 8 cm, and the upper wall portions 203-206 preferably have a height of about 7 cm so that the total height of the transport container is about 15 cm. The grooves 7 a-7 d and 8 a-8 d are formed through the upper wall portions 203-206 and between outwardly protruding wall sections 207 a-207 d as shown in the cross sectional view of FIG. 19. A possible design of the grooves 7 a-7 d is shown in FIG. 19, for example, with the grooves 8 a-8 d in the opposed side wall are identical. In this way, by means of such a construction of the grooves 7 a-7 d and 8 a-8 d a plurality of strengthening ribs are formed on the outside of the upper wall portions 205 and 206 for increasing the stability of the transport container 50.

As shown in FIGS. 17 a, 17 b and 19, the guide pegs 12 a-12 d and 13 a-13 d have different shapes. The two outer guide pegs 12 a, 12 d, 13 a and 13 d have a drop shape, and the inner guide pegs 12 b, 12 c, 13 b and 13 c have a substantially semi-circular shape. The outermost ends of all guide pegs are provided with downwardly extending protrusions (213 a and 213 b in FIGS. 17 a and 17 b, for example) adapted for engaging with an rib or edge (406 in FIG. 18) formed at the upper surface of the upper wall portions of the side walls. These protrusions can also engage with the support surface of the groove stops (10 a-10 d in FIG. 19) when both transport containers are placed inside one another. By means of the drop shape (see guide peg 13 a in FIG. 17 b) or by means of the semi-circular shape (see guide peg 13 b in FIG. 17 a) of the guide pegs insertion of the guide pegs into the grooves is facilitated.

Preferably, the guide pegs 13 a and 13 b have a distance of about 13 cm. Preferably, the guide pegs 13 b and 13 c have a distance of about 16 cm. Preferably, the guide pegs 13 c and 13 d have a distance of about 13 cm. The guide pegs 12 a-12 d on the opposite side wall have the same distances. Preferably, the recesses 16 a and 16 b have a distance of about 13 cm. Preferably, the recesses 16 b and 16 c have a distance of about 16 cm. Preferably, the recesses 16 c and 16 d have a distance of about 13 cm. The recesses 17 a-17 d on the opposite side wall have the same distances. Preferably, the groove openings 21 a and 21 b have a distance of about 13 cm. Preferably, the groove openings 21 b and 21 c have a distance of about 15 cm. Preferably, the groove openings 21 c and 21 d have a distance of about 10.5 cm. The groove openings 22 a-22 d on the opposite side wall have the same distances.

FIGS. 20 a, 20 b, 21 a, 21 b and 22 a, 22 b show particularly preferred configurations of the transport container of the present invention. In these configurations, a plunge movement of the upper container into the container underneath is possible in one direction only. Thereby, “mixed” insertion inside one another of a plurality of transport containers stacked one above the other is prevented. Therefore, also unstacking is conducted in only one direction, with the advantage that the packing personnel or the packing apparatus must work in one direction only. The advantage thereof consists in the fact that a stack of transport containers, positioned directly in front of a wall or in front of another stack of containers, must not be pulled forward when a incorrectly stacked container has to be removed from the stack in rearward direction (instead in forward direction). It is obvious that this feature is very important with respect to empty containers inserted one into another.

As can be seen in FIGS. 20 a and 20 b, the transport container comprises two guide pegs 500 a-d and two grooves 502 a-d at each side thereof. The distances between the groove openings 503 a-d at each side are different from the distances between the corresponding guide pegs. It is obvious that the above described plunge movement is also necessary in this case to insert an upper container into the container underneath. It is also obvious that said plunge movement is possible in one direction only such that an incorrect plunge movement (i.e. from the opposite direction) is not possible.

In FIGS. 21 a and 21 b, a modification of the container of FIGS. 20 a and 20 b is shown. At this container, three guide pegs 600 a-f and three grooves 602 a-f are provided at each side. The distances between the groove openings 603 a-f at each side are different from the distances between the corresponding guide pegs. Further, the distances between the guide pegs 600 a-f are different at each side of the container. Thus, it is obvious that the above described plunge movement is also necessary in this case to insert an upper container into the container underneath, and that said plunge movement is possible in one direction only such that an incorrect plunge movement (i.e. from the opposite direction) is not possible. In FIGS. 21 a and 21 b, it can also be seen that the central guide pegs 600 b, e are positioned slightly deeper than the two outermost guide pegs 600 a, c, d, f.

In FIGS. 22 a and 22 b, a further modification of the container of FIGS. 20 a,b and 21 a,b is shown. At this container, four guide pegs 700 a-f and four grooves 702 a-f are provided at each side. The distances between the groove openings 703 a-h at each side are different from the distances between the guide pegs. Further, the distances between the guide pegs 700 a-h are all different at each side of the container. Thus, it is obvious that the described plunge movement is necessary to insert an upper container into the container underneath, and that said plunge movement is possible in one direction only such that an incorrect plunge movement (i.e. from the opposite direction) is not possible. A plunge movement from opposite directions is not possible as the distances of the guide pegs are not symmetrically distributed (i.e. the distances between the two outer guide pegs are the same, but are different from the distances between the two central guide pegs), instead, all three distances at each side are different from each other. In FIGS. 22 a, 22 b, it can also be seen that the central guide pegs 700 b, c, f, g are positioned slightly deeper than the two outermost guide pegs 700 a, d, e, h.

A further important aspect of the invention, shown in FIGS. 20 a, 20 b to 22 a, 22 b, consists in the fact that a reinforcement rib VR is formed at each of the guide pegs. The reinforcement rib VR may either be formed by a suitable reinforcement of the material (i.e. the material is thicker at the rib) or by a suitable shaping of the material at the sidewalls at the reinforcement ribs. In each case, the strength of the guide pegs is substantially improved such that breaking of the guide pegs is effectively prevented. In this way, it is possible to avoid the use of expensive plastic material which is reinforced with glass fibers, for example. Instead, a conventional plastic material may be used. As the technically complex mixing of glass fiber particles into the plastic material may be avoided, material costs and production costs can be substantially reduced.

Another important feature is the configuration of the guide pegs G itself and the configuration of the guide groove FN. As diagrammatically shown in FIG. 23, the guide groove FN of a container B according to the invention comprises a sloped side surface 800 which is adapted to engage with a correspondingly sloped surface 801 of a slide rib 803 formed at a bottom side of the guide peg 802 of an upper container B. It is obvious that the sidewall of the lower container B even in case of applying high forces by the upper container, i.e. via the respective guide peg 802, not being pushed in outward direction, which would result in that the guide pegs disengage from the upper edge of the side wall of the lower container. Instead, the side wall is pushed in inward direction by means of the engagement of the correspondingly sloped surfaces 800 and 801 of the guide groove FN and the slide ribs 803, thereby preventing disengagement even in case of applying high forces by the upper container. 

1-27. (canceled)
 28. Stackable transport container comprising a bottom, a front wall, a rear wall, a left side wall and a right side wall to form a receptacle open towards the top; characterized in that in the left side wall and in the right side wall at least two grooves are formed, respectively, which grooves have upper groove openings and lower groove stops; that at the lower edge of the outside of the left side wall and at the lower edge of the outside of the right side wall at least two guide pegs are formed, respectively; that the distances between the guide pegs are different from the distances between the respective upper groove openings; that the distances between the guide pegs are equal to the distances between the respective lower groove stops; that the distances between the guide pegs at each of the sides are all different; and that the distances between the guide pegs are chosen such that a plunge movement of an upper container into a container underneath is possible only in one direction.
 29. Stackable transport container according to claim 28, characterized in that in the upper edges of the right side wall and of the left side wall at least two recesses are formed, respectively, and that the distances between the recesses are equal to the distances between the respective guide pegs.
 30. Stackable transport container according to claim 28, wherein the grooves are inclined relative to the vertical and each have a different slope, curve and shape.
 31. Stackable transport container according to claim 28, wherein the individual grooves, guide pegs and recesses of the left side wall are each identical to the respective individual opposite grooves, guide pegs and recesses of the right side wall.
 32. Stackable transport container according to claim 28, wherein the grooves at the inner side of the side walls are formed in the shape of channels.
 33. Stackable transport container according to claim 28, wherein the grooves extend through the respective side walls, thereby forming slits through the walls.
 34. Stackable transport container according to claim 28, wherein the outermost ends of the guide pegs are provided with downwardly extending protrusions.
 35. Stackable transport container according to claim 34, wherein the downwardly extending protrusions provided at the outermost ends of the guide pegs comprising inwardly inclined surfaces.
 36. Stackable transport container according to one claim 28, wherein the grooves have a width that is somewhat greater than the diameter of the guide pegs.
 37. Stackable transport container according to claim 28, wherein the groove stops lie in a horizontal plane.
 38. Stackable transport container according to claim 37, wherein the horizontal plane lies close to the middle of the transport container.
 39. Stackable transport container according to claim 28, wherein the guide pegs lie in one horizontal plane.
 40. Stackable transport container according to claim 39, wherein the horizontal plane lies close to the bottom of the transport container.
 41. Stackable transport container according to claim 28, wherein the height of the side walls is equal to the height of the front wall and the rear wall.
 42. Stackable transport container according to claim 28, wherein the height of the side walls is greater than the height of the front wall and the rear wall.
 43. Stackable transport container according to claim 28, wherein the upper surface of the site walls and/or of the front wall and/or of the rear wall being provided with upward extending ribs.
 44. Stackable transport container according to claim 28, wherein the upper surface of the side walls being provided with a guide groove.
 45. Stackable transport container according to claim 44, wherein the guide groove being provided with an inwardly inclined surface.
 46. Stackable transport container according to claim 28, wherein the guide pegs being provided with reinforcing ribs.
 47. Stackable transport container according to claim 46, wherein the reinforcing ribs being provided being provided at the outer side of the side walls and substantially having the shape of the grooves at the opposite inner side of the side walls.
 48. Stackable transport container according to claim 46, wherein the reinforcing ribs being formed by deformation of the side walls adjacent to the guide pegs.
 49. Stackable transport container according to claim 46, wherein the reinforcing ribs being formed by increasing the thickness of the material of the side walls adjacent to the guide pegs.
 50. Stackable transport container according to claim 46, wherein the reinforcing ribs having different width and thickness.
 51. Stackable transport container according to claim 46, wherein the reinforcing ribs having variable width and thickness.
 52. Stackable transport container according to claim 46, wherein the reinforcing ribs being formed by protruding channels.
 53. Stackable transport container according to claim 46, wherein the reinforcing ribs being formed by impressing of material wherein the grooves are partially formed by the opposite side. 